What is the primary function of an electrician's multimeter?

The primary function of an electrician's multimeter is to measure voltage, current, and resistance, which makes option B the correct choice. A multimeter is an essential tool in electrical work, as it enables electricians to assess the electrical characteristics of circuits and components accurately.

Measuring voltage allows the electrician to determine if a circuit is energized and operating within its specified limits, ensuring safe and effective functionality. Measuring current is crucial for understanding how much electrical flow is present in a circuit, which can help identify overloads or faults. Lastly, measuring resistance is vital for troubleshooting, as it helps establish the integrity of the connections in a circuit and the functionality of other components.

While connecting different electrical devices and inspecting circuit breakers are important tasks in electrical work, they do not represent the core purpose of a multimeter. Testing insulation quality is a specialized task that may require specific instruments like an insulation resistance tester, rather than a general-purpose multimeter. Thus, understanding the multimeter's capabilities in measuring electrical parameters highlights its primary function in an electrician's toolkit.